Wireless receiving set



March 27, 1928. 1,664,192

F. CONRAD WIRELESS RECEIVING SET Filed July ll. 1922 ATTORN EY l. ffff@ Patented AMar. 27, 1928.

UNITED STATES PATENT OFFICE.

FRANK CONRAD, 0F- PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION 0F PENNSYLVANIA.

WIRELESS RECEIVING SET.

Application led July 11,

My invention relates to wireless telegraphy and particularly to circuits and apparatus adapted for embodiment in wireless receiving sets.

One object of my invention is to provide a cabinet of simple, compact and rugged design adapted to embody a complete radio-` receiving set which is characterized by its extreme simplicity of operation andthe absence of complicated adjustments.

Another object of my invention is to provide a wireless receivin set of such design as to admit of inexpensive quantity production with existing manufacturing methods.

Still another object of my invention is to provide a receiving system,embodying kantenna l and detector circuits wherein extremely sharp tunin of the antenna circuit may be effected wit out decreasing the efiiciency of the detector circuit.

In order to obtain sharp tuning in the antenna circuit, it is necessary that the cir-` cuit have a relatively large amount of inductance and a relatively small lamount of capacitance.

If the antenna inductance and capacitance lconstants are adjusted as just mentioned, as

by means of a variometer having a large inductive reaction and a condenser having a large capacitive reaction, and the detector circuit is connected in shunt relation to the variometer, optimum operating conditions are not obtained, since the energy loss in the 4antenna circuit and the detector circuit are, in general, not equal.

According to my invention, I provide a 1922. Serial No. 574,316.

compartment is provided with a control panel constituting a top cover for the lcompartment. The control panel may also serve as a support for the wave-responsive apparatus `in a manner hereinafter described. A movable lid may be provided for the box enclosing a space between itself and the concuits and apparatus embodying my invention;

Fig. 2 is a top plan view of the unitary structure or box adapted to contain the circuits and apparatus, except the antenna and the ground connection, shown in Fig. 1.

Eig. 3 is a side elevational view, shown partially in section on the line III-III of Fig. 2, with the cover removed.

In Fig. 1 is shown a wireless receiving system- 1 adapted for embodiment in a unitary structure or box 12, as shown in Figs. 2 and 3. The receiving system 1 comprises an antenna circuit 3 and a detector circuit 4 operatively associated therewith. The antenna circuit 3 comprises an antenna 5, a down lead 6,y a wave-changing arrangement 7, a variometer 8 having relatively stationary and movable coils 9 and 11, respectively, a ground .binding post 12 and a ground conductor 13 therefor.

The wave-changing mechanism 7 comprises a pair of serially connected condensers'14 and 15, one terminal of the pair being connected by a iiexible conductor 16 to one end of the movable variometer element 11. A pair of binding posts 17 and 18 are connected to the remaining terminal of said pair of condensers and to a point intermediate the same to provide relatively short or lo wave connections for the antenna down ead 6. The detector circuit 4 extends from the ground terminal 13 to a tap point 19 on the stationary coil 9 of the variometer 8 and includes a detector 21 and 100 isisA gewone@ ably mounting the other 'emi of mid mi@ in perforation in sant insueting Meek, whereby such manneethat said secone fefn may be saio bleek may @eme as e suppezt fer seid earrie thereby, an insulating beck secured leed. f

to said rodi an@ provided with a perforation in testimony Wheleo, have hezeunt@ `5 extending to the ateml surface thereof, and subscribed my name this 5th day July? a exible Aterminal lead of the movable eei922. ment of the variometer., said lead extending@1 from said movabe element through the FRANK CONRAD. 

